The cell is always running but the spark job has been successful

[icankeep]

hello, I start spark in the scala kernel through the following code

import org.apache.log4j.{Level, Logger}
Logger.getLogger("org").setLevel(Level.OFF)

import org.apache.spark.sql._
import org.apache.spark.{SparkConf, SparkContext}
val conf = {
    new SparkConf()
    .setAppName("Jupyter")
    .setMaster("yarn")
    .set("spark.yarn.queue", "foo")
    ...
}
val spark = {
  NotebookSparkSession
    .builder
    .config(conf)
    .enableHiveSupport.getOrCreate
}

but sometimes when I run spark sql, the cell will always keep running, but it shows that the job has run successfully on spark ui, it seems to be a bug, how can I solve it?